INTEL HOUSE

As computer technology advances, your computer will react more slowly, taking more time to process events. Luckily, computers can be easily upgraded. Upgrading your CPU (Central Processing Unit) is one of the most beneficial and easiest things you can do to make your computer run lag-free.

[edit] Steps

Part 1: Identification
Turn off your PC and remove the power cable.
Unscrew your computer's case and remove the cover.
Identify your motherboard, your current processor chip, your RAM memory cards, and your video card.
Find out what socket your motherboard has. Do a Google search or ask a computer technician if your current motherboard model supports a Pentium 4 or an Athlon 64 processor.The major sockets are:
Socket 370: Intel Pentium III, Celeron.
Socket 462 (socket A): AMD Athlon, Duron, Athlon XP, Athlon XP-M, Athlon MP, Sempron.
Socket 423: Pentium 4.
Socket 478: Intel Pentium 4, Celeron, Pentium 4 Extreme Edition.
Socket 479 (mobile): Intel Pentium M, Celeron M, Core Solo, Core Duo.
Socket 754: AMD Athlon 64, Sempron, Turion 64.
Socket 775: Intel Pentium D, Pentium 4, Celeron D, Pentium Extreme Edition, Core 2 Duo, Core 2 Quad.
Socket 939: AMD 64, Athlon 64 X2, Athlon 64 FX, Sempron, Opteron.
Socket 940: AMD Athlon 64 FX, Opteron.
Socket AM2/AM2+: AMD Athlon 64, FX, Opteron, Phenom
If your current motherboard does support a Pentium 4 or Athlon 64 processor, jump to Part 2. If not, continue to Part 3.

Part 2: Buying a Pentium 4 Processor/Athlon 64
Buy the new processor at a computer hardware store of your choice.
Jump to Part 4.

Part 3: Buying a New Motherboard
Choose a motherboard that satisfies your criteria (which may depend on cost, technical specifications, or compatibility with your old hardware).
If compatibility exists with all the old hardware, jump to Part 5.
Investigate the compatibility of your video card and RAM memory.
If there is no compatibility with the video card or the new motherboard does not have a integrated video card on the motherboard, buy a new compatible video card.
If the new motherboard does not support the old RAM memory, buy new compatible RAM memory cards.
Jump to Part 5.

Part 4: Replacing the Processor

Desktop Units
Take out your old CPU. Open up your case, unclip the Heatsink off the retaining board, and pull the the heatsink off. Some heatsinks require a screwdriver or other proprietary tool to remove (Zalman is notorious for this).
Open the lever on the side of the socket. Do this by pulling it out, and then pulling it up. Gently lift your old CPU off of the socket.
Take the new CPU out of the box. Line up the gold triangle on the CPU with the one on the socket, and gently let the CPU fall in place. Do not force the CPU. If it is lined up correctly, it will drop right into place.
Close the ZIF (zero insertion force) lever to lock the CPU. Take the included heatsink and clip it on using the instructions. If your heatsink doesn't have thermal paste or pads on it yet, apply a very thin layer of it. The thermal paste acts as a conductor, transferring the heat from the processor chip to the heat sink. If the heatsink includes a fan, plug it into its proper connector. Do not operate a CPU without thermal transfer material or a heatsink in place.
Jump to Part 6.

Socket 479 and other mobile sockets
If there is a screw, unscrew it off the socket. Now pull the CPU out.
Push the new CPU in, lining it up like before.
It will either be pushed in and held by force or a spring mechanism, or screwed in place.
Once you have the CPU, it may or may not need a heatsink. Look at your CPU manual.
Power up and enjoy your upgraded computer!

Part 5: Replacing the Motherboard
Label each cable that is connected to the old motherboard and take note of the place where the cable comes from. Some small cables have a name written beside the port where it connects to the motherboard. This is usually very small. For example, it may read "FAN1" if it is a fan's power cable.
Remove all the cards connected to the motherboard.
Remove all cables connected to the motherboard.
Remove the old processor with extreme care and store it in a static-free environment (plastic bags for this purpose are sold at Radio Shack).
Unscrew and remove the old motherboard.
Replace the motherboard.
Replace the motherboard screws.
Insert the new processor.
Make sure your new processor is correctly placed and fastened to the motherboard.
Rewire the motherboard.
Re-card your motherboard (all of the cards go in the place they fit in).
Go to Part 6.

Part 6: Reassembling the Computer
Put the PC's cover back on.
Replace the screws in the case.
Rewire the power cord, keyboard, mouse, monitor, and other connections.
Test your work of art.

[edit] Tips
Do a lot of research on your current hardware specs to ensure that the processor you intend to upgrade to is compatible with your motherboard. If it's not, you will need to purchase a new motherboard.
In order to get to your processor, you might need to unscrew, remove, or disconnect other PC components such as IDE cables and various PCI cards. Make sure you know where these components go and how they are connected to your motherboard before you attempt to upgrade your processor.
If your computer does not turn on after this, it could be due to one of the following reasons:
You might have misplaced a cable on your motherboard, or you may not have fastened down your processor correctly.
Remember, technical work always requires a lot of prior investigation for things to go right, so take your time and don't try and rush it. Remember, patience is a virtue.
If you feel things are going wrong and you have messed up badly, start all over again by unscrewing and removing everything.
If you do decide to purchase a new motherboard, remember that the cheapest motherboard is not always the best motherboard for your system. You might require extra components in the long run, so make sure that if you do intend to purchase a new motherboard in addition to upgrading your processor, it has a few extra features. You may possibly make use of them one day.
In order to properly discharge static electricity, you either need to wear a grounding strap attached to the case for 5-10 minutes before you begin work, or simply leave the computer unplugged. You can make your own grounding cable. To do this, re-wire a power cord with the hot and neutral pins disconnected, leaving only the ground. You can also buy these ready-made. Always touch the case prior to working to discharge any static.
You may need to flash (update) BIOS to support new technology such as dual core or Hyperthreading. Do this before you put the new CPU in.
If your CPU has an IHS don't be scared to push hard to get the heatsink clipped in place. If your CPU has a bare core you will need to be more careful not to crush or chip the core. If you do damage the core, there is no salvaging the CPU.

[edit] Warnings
Do not touch the top of the processor chip or the gold pins at the base of various PCI cards with your bare hands. You may damage them.
If your computer still has a warranty, avoid using these instructions. You may void your warranty.
If you are scared of damaging a component, do not attempt these procedures, as there is always a risk.
NEVER Attempt to start the computer or run it without the Heatsink in place over the CPU. With an AMD CPU you will most certainly burn it out within seconds, an Intel CPU should slow down to protect itself from damage - even so, please don't try it! This is not covered by the warranty. Do not attempt to run a CPU without thermal material, or a heatsink in place. On most desktop systems, you will need both. Doing so can damage your processor beyond repair, and also void the manufacturer's warranty.
As always, ESD (Electrostatic Discharge) will kill electronics. Be sure to periodically ground yourself by touching the case. Or you can use an anti-static wrist band. Other than that this is a fail safe operation if done with common sense.